Vehicle Motion…Car, Boat, Spaceship

I usually do not put code inside frames, but here you will have to, because I didn’t write the code.

The code was taken from “Beginning Flash Game Programming For Dummies”. I have been trying to add the code so that it will stop the car/boat/spaceship from passing through the walls I make, but since there moving to fast, I can’t. If I figure out the code, I will post it, but if you figure the code…well…post it! Thank you.

I hope you enjoy this tutorial.
The code was taken from “Beginning Flash Game Programming For Dummies”.

Car:

Step 1 ~ Draw a car, or anything that moves like a car.
Step 2 ~ Convert it to a movieclip, call it whatever you want. I prefer “player”.
Step 3 ~ Give it the instance name of “car”.
Step 4 ~ Copy and paste this code to the frame the car is in, remember, I said FRAME.
________________________________________________________________
//carVector
//use vector projection to go any speed, any direction

init();
function init(){
  car.speed = 0;
  //direction is now in degrees
  car.dir = 33;
}

car.onEnterFrame = function(){
  checkKeys();
  turn(car);
  move(car);
} // end enterFrame

function turn(sprite){
  //use vector projection to get DX and DY

//offset the angle
  degrees = sprite.dir -90;

//convert to radians
  radians = degrees / 180 * Math.PI;

//get DX and DY (normalized: length is one)
  sprite.dx = Math.cos(radians);
  sprite.dy = Math.sin(radians);

//compensate for speed
  sprite.dx *= sprite.speed;
  sprite.dy *= sprite.speed;
} // end turn;

function move(sprite){
  //moves any sprite, wrapping around boundaries

//move
  sprite._x += sprite.dx;
  sprite._y += sprite.dy;

//rotate changed slightly.
  sprite._rotation = sprite.dir;

//check boundaries – wrap all directions
  if (sprite._x > Stage.width){
  sprite._x = 0;
  } // end if

if (sprite._x < 0){
  sprite._x = Stage.width;
  } // end if

if (sprite._y > Stage.height){
  sprite._y = 0;
  } // end if

if (sprite._y < 0){
  sprite._y = Stage.height;
  } // end if
} // end move

function checkKeys(){
  //check keyboard to move car
  if (Key.isDown(Key.UP)){
  car.speed++;
  if (car.speed > 8){
  car.speed = 8;
  } // end if
  } // end if

if (Key.isDown(Key.DOWN)){
  car.speed–;
  if (car.speed < -3){
  car.speed = -3;
  } // end if
  } // end if

if (Key.isDown(Key.RIGHT)){
  car.dir += 5;
  if (car.dir > 360){
  car.dir = 0;
  } // end if
  } // end if

if (Key.isDown(Key.LEFT)){
  car.dir -= 5;
  if (car.dir < 0){
  car.dir = 360;
  } // end if
  } // end if

} // end checkKeys
________________________________________________________________

If you have any questions, ask me, thanks for reading, and remember to show me what you made with this. Thanks.

Boat:

Step 1 ~ Draw a boat, or anything that moves like a boat.
Step 2 ~ Convert it to a movieclip, call it whatever you want. I prefer “player”.
Step 3 ~ Give it the instance name of “boat”.
Step 4 ~ Copy and paste this code to the frame the boat is in, remember, I said FRAME.
________________________________________________________________________
//boat movement
//simulate a boat with drift friction

init();

function init(){
  //create the boat

boat.dx = 0;
  boat.dy = 0;
  boat.speed = 0;
  boat.dir = 0;
  boat.drag = .9;
  boat.traction = .5;
} // end init

boat.onEnterFrame = function(){
  boat.checkKeys();
  boat.turn();
  boat.move();
} // end if

boat.checkKeys = function(){
  //check for left and right arrows
  if (Key.isDown(Key.LEFT)){
  this.dir -= 10;
  if (this.dir < 0){
  this.dir = 350;
  } // end if
  } else if (Key.isDown(Key.RIGHT)){
  this.dir += 10;
  if (this.dir > 360){
  this.dir = 10;
  } // end if
  } else if (Key.isDown(Key.UP)){
  //thrust on up arrow
  this.thrustSpeed = 1;
  } else {
  this.thrustSpeed = 0;
  } // end if
} // end checkKeys

boat.turn = function(){
  this._rotation = this.dir;

//get new thrust vector
  //thrust vector is direction boat is currently pointing
  degrees = this.dir
  degrees -= 90;
  radians = degrees * Math.PI / 180;

//calculate current speed
  speed = Math.sqrt(this.dx * this.dx + this.dy * this.dy);

driftDX = Math.cos(radians);
  driftDY = Math.sin(radians);

//adjust driftDX for speed BEFORE applying thrust.
  driftDX *= speed;
  driftDY *= speed;

thrustDX = this.thrustSpeed * Math.cos(radians);
  thrustDY = this.thrustSpeed * Math.sin(radians);

//add thrust to dx and dy
  this.dx += thrustDX;
  this.dy += thrustDY;

//compensate for drag;
  this.dx *= this.drag;
  this.dy *= this.drag;

} // end turn

boat.move = function(){
  //move according to current speed BEFORE applying thrust.
  this._x += driftDX * this.traction;
  this._y += driftDY * this.traction;

//move again AFTER applying thrust
  this._x += this.dx * (1/this.traction);
  boat._y += this.dy * (1/this.traction);

//wrap around screen
  if (this._x > Stage.width){
  this._x = 0;
  } // end if

if (this._x < 0){
  this._x = Stage.width;
  } // end if

if (this._y > Stage.height){
  this._y = 0;
  } // end if

if (this._y < 0){
  this._y = Stage.height;
  } // end if

} // end move
________________________________________________________________________

Kind of the same as the car, right? Well, that’s the good part about it.

Spaceship:

Step 1 ~ Draw a spaceship or anything that moves like one.
Step 2 ~ Convert it to a movieclip, call it whatever you want. I prefer “player”.
Step 3 ~ Give it the instance name of “myship”.
Step 4 ~ Copy and paste this code to the frame the spaceship is in, remember, I said FRAME.
________________________________________________________________________
//ship movement
//simulate a space ship no friction

init();

function init(){

//normal initialization
  myShip.dx = 0;
  myShip.dy = 0;
  myShip.speed = 0;
  myShip.dir = 0;
  myShip.gotoAndStop(“still”);
} // end init

myShip.onEnterFrame = function(){
  myShip.checkKeys();
  myShip.turn();
  myShip.move();
} // end if

myShip.checkKeys = function(){
  //check for left and right arrows
  if (Key.isDown(Key.LEFT)){
  this.dir -= 10;
  this.gotoAndStop(“left”);
  if (this.dir < 0){
  this.dir = 350;
  } // end if

} else if (Key.isDown(Key.RIGHT)){
  this.dir += 10;
  this.gotoAndStop(“right”);
  if (this.dir > 360){
  this.dir = 10;
  } // end if
  } else if (Key.isDown(Key.UP)){
  //thrust on up arrow
  this.thrustSpeed = 1;
  this.gotoAndStop(“thrust”);
  } else {
  this.thrustSpeed = 0;
  this.gotoAndStop(“still”);
  } // end if
} // end checkKeys

myShip.turn = function(){
  this._rotation = this.dir;
  //trace(“I’m here…”);

//get new thrust vector
  degrees = this.dir
  degrees -= 90;
  radians = degrees * Math.PI / 180;
  thrustDX = this.thrustSpeed * Math.cos(radians);
  thrustDY = this.thrustSpeed * Math.sin(radians);

//add thrust to dx and dy
  this.dx += thrustDX;
  this.dy += thrustDY;

} // end turn

myShip.move = function(){
  this._x += this.dx;
  this._y += this.dy;

//wrap around screen
  if (this._x > Stage.width){
  this._x = 0;
  } // end if

if (this._x < 0){
  this._x = Stage.width;
  } // end if

if (this._y > Stage.height){
  this._y = 0;
  } // end if

if (this._y < 0){
  this._y = Stage.height;
  } // end if

} // end move
________________________________________________________________________

Step 5 ~ Inside the spaceship (double click it), label the first frame, “still”.
Step 6 ~ Make another frame, label it, “right”, and draw the ship the way you want it to look when its moving right…Don’t rotate it, the code does that for you.
Step 7 ~ Make another frame, label it, “left”, and draw the ship the way you want it to look when its moving right…Remember, don’t rotate it.
Step 8 ~ Make yet another frame, label it, “thrust”. Draw the ship the way you want it to look when its moving forward. Remember not to rotate it.

The space ship was a bit’ harder and longer to make. But the ship is also very unique, and fun to drive it. Now, go on! Make a game with this! Remember to tell me what you made with this tutorial.

Any questions you have, ask me, I will help…if…well…if I can. Bye!

Files: Car, Boat, SpaceShip.

WARNING:

I fixed the problem, it should all work now.